Speed regulator for machine guns



Dec. 31, 1929. c, PFEIFFER 1,741,534

SPEED REGULATOR FOR MACHINE GUNS Original Filed July 12, 1927 fnyewtar Christian FfejffEz" tarngy Patented Dec. 31, 1929 CHRISTIAN PFEIFFER, 0F HARTFORD, CONNECTICUT, ASSIGNOR TO COLTS PATENT FIRE ARMS MANUFACTURING COMPANY,

POR-ATION OF CONNECTICUT OF HARTFORD, CONNECTICUT, A COR- SPEED REGULATOR FOR MACHINE GUN'S Application filed July 12, 1927, Serial No. 205,210. Renewed March 14, 1929.

In the use of automatic machine guns it is frequently desirable to regulate the rate of firing and to avoid the very rapid firing which ordinarily takes place. It has been found that in automatic machine guns the rate of firing may be so rapid when the gun is being operated with its full automatic action as to be positively disadvantageous. The rate of firing may be so rapid that the shooter cannot properly aim his gun, with the result that ammunition is wasted and that the succession of shots is so rapid that the gun heats up too rapidly and that the rifling in the barrel wears out too quickly. It has, therefore, been found advisable to provide means to retard the rate of firing by ensuring a lapse of time between successive shot-s greater than the time required for the usual recoil and return to battery of the recoiling parts.

The general object of the present invention is to provide a regulating or retarding mechanism of simple and compact construction adapted to be readily adjusted to provide different retarding effects as may be desired.

A further object of the invention is to provide a regulating or retarding mechanism Which is adapted to be readily attached to or removed from the gun without necessitating any major changes in the structure of the gun itself.

Still further objects of the invention will be apparent from the following specification and claims.

In the accompanying drawing I have shown one embodiment of the invention but itwill be understood that the drawing is for illustrative purposes only and is not to be construed as defining or limiting the scope of the invention the claims forming a part of this specification being relied upon for that purpose.

01 the drawing.

l" 1 is a side view of a mechanism embodying the invention, certain parts of the mechanism being hOWD in section. T his view also shows in outline a part of un with which the mechanism may be used.

F 2 is an end portion of the parts shown in Fig 1 this View being taken from the front.

Fig. 3 is a View similar to Fig. 1 but showing the parts in different relative positions.

In order that the invention may be clearly understood I have illustrated it as applied to a gun of the type shown in the Browning Patent 1,628,226 dated May 10, 1927. It will be understood that the invention while illustrated in conjunction with the gun shown in the said patent may be, with suitable modifications, applied to other guns having longitudinally reciprocating recoil operated members.

The gun as an entirety is represented by G. This gun comprises a breech casing which may comprise side plates 1 and 2 and top and bottom plates 3 and 4. The mechanism of the gun includes a recoil-operated reciprocating breech block (not shown) and also includes a stud or member 5 which is carried by or forms a part of the breech block and which pro ects laterally therefrom through a 1011- gitudinal slot 6 in the breech casing. The member 5 ordinarily serves as a handle for the manual operation of the gun.

The speed regulating mechanism includes a regulating element which automatically engages a reciprocating member of the gun, in this case the stud 5 on the breech block, during the initial part of its counter-recoil movement and which is then automatically disengaged from the reciprocating member in order to permit the reciprocating member to complete its counter-recoil movement independently of the regulating element. In conjunction with the regulating element there is provided a means for retarding the move ment thereof and for thus retarding the aforesaid initial part of the counteri'ecoil movement of the reciprocating member. In addition there is provided automatic means which act after the disengagement of the reciprocating member from the regulating element and preferably during the recoil movement for returning the regulating element-to its position of initial engagement with the said member. The essential parts of the regulating mechanism as outlined may be varied Widely as to details of construction. I prefer to construct the regulating e ement in the form of a lever T which is provided at S for movement about a pivotal axis perpendicular to the direction of movement of the stud or member 5, the said axis preferably being horizontal. The regulating element or lever 7 is so constructed and positioned that it automatically engagesthe reciprocating member during the initial part of the counter-recoil movement thereof. Thereafter it is automatically disengaged from the said reciprocating member so as to permit the member to complete its counter-recoil movement independently of the regulating element. lVhen the regulating element is a pivoted lever as shown and described there is provided an upward extending lug 7 on the lever with which the front side of the member 5 directly engages. of the lover carries the said lug 7 out of the path of movement of the reciprocating member the said member being then free to continue its counter-recoil movement toward the right independently of the lever. By dotted lines in Fig. 1 l have shown the position of the lever 7 at the beginning of the counterrecoil movement and by full lines in the same figures l have shown the lever 7 at the position of disengagement.

As already stated I provide means connected with the regulating element or lever for retarding the movement thereof and thereby retarding the initial part of the counter-recoil movement of the reciprocating member. Preferably this retarding means comprises a cylinder and a piston movable therein one of the said elements being directly connected with the said regulating element. As illustrated there is a cylinder 9 normally rigidly secured in place with respect to the gun and there is provided a piston 10 which lits the interior of the cylinder and is longitudinally movable therein. The piston 10 is mounted upon a piston rod 11 which extends through a suitable stuiiing box at 12 and is connected with the lever 7 by means of a pin 13 extendin through a slot let in the lever. The cylinder 9 is filled with a noncompressible liquid, such as oil, and I provide a pasand a check valve therefor permitting the liquid to flow freely from one end of the cylinder to the other during recoil but preventing such llow in the reverse direction during counterecoil. As illustrated the passage is formed in the piston 10 and may be in the form of a plurality of holes 15, 15. The check valve is in the form of a disc 16 which surrounds a hub 17 on the pistonand is held against removal by a nut 18. The disc 16 is free to move longitudinally within the space between the piston 10 and the nut 18 and during the counter-recoil movement the action of the liquid forces the disc against the piston as shown in Fig. 1 thus entirel closing the holes 15, 15. lVith the holes closed as shown in Fig. 1 movement of the piston is retarded thus retarding movement ll e arcuate movement In order that the retardin action of the cylinder andpiston maybe adjusted 1 provide in addition to the holes 15, another passage connecting the two end portions of the cylinder, thispassage preferably being formed outside of t 1e cylinder proper. As illustrated there is provided a passage 19 below the cylinder proper this passage communieating with the end portions of the cylinder by means of holes 20 and 20". A means is provided for adjusting the effective cross-sectional area of the passage 19 and as shown this means is in the form of a conical valve closure 21 which is adapted to engage or substantially engage a valve seat 22 adjacent one end of the passage. The valve closure 21 is mounted on a valve stem 28 which is threaded at 24 to engage internal threads formed in a bushing 25. A stufling box 26 prevents leakage of oil along the valve stem. A hand wheel or knob 27 is provided for turning the valve stem and for thus adjusting the position of the valve closure 21. It will be obvious that if the passage 19 were entirely closed by the closure 21 the retarding effect upon the lever 7 would be so great as to almost entirely prevent the movement thereof, movement being permitted only by reason of leakage past the piston 10 and past the valve disc 16. However, by slightly moving the valve closure 21 from its seat a restricted opening is provided through the passageway 19 thus permitting a limited flow of oil from one end of the piston to the other and thus permitting the element 7 and the reciprocating member 5'to move slowly. Obviously the rate of movement can be adjusted at will by turning the knob 27 and thus changing the position of the valve closure 21.

As soon as the reciprocating member is disengaged from the regulating element it is moved by the reaction spring of the gun to the firing position in the usual way. Upon firing, the reciprocating member is moved by the recoil action to the rear positionv shown by dotted lines in Fig. 1. I provide automatic means which act after the disengagement of the member 5 from the regulating element to restore said element to its position of initial engagement as shown by dotted lines in Fig. 1. "the said means may be operatively dependent upon the recoil movement of the gun and may act during such movement; and in fact the said means may be operated independently of any other parts of the firearm directly by the same member which is retarded. When the regulating element is a lever such as 7 the means for re turning the lever to its initial position preferably comprises an extension or lug 7' formed integrally with the main body of the lever 7 and positioned to be engaged by the rear side of the stud 5. Thus the lever 7 comprises two extensions or lugs, that is, the aforesaid lug 7 and the lug 7 last above described, the stud 5 being received between these two lugs when in the rear portion of its path of movement.

Preferably the projection or lug 7 of the lever, instead of being formed integrally with the main body thereof, is constructed in the form of an inward. movable latch or plunger which is normally held in its outer position by means of a spring 28. This resilient mountii'ig of the lug 7" is for the purpose of preventing any possible damage such as might occur if the regulating lever 7 should be accidently moved slightly in the counterclockwise direction while the stud 5 is in the forward portion of its path of movement. ()bviously if the lever 7 were so moved the stud 5 upon recoil would, instead of being received between the two lugs 7 and 7 engage the top of the lug 7 and perhaps do serious damage to the entire mechanism. With the lug 7 resiliently mounted, however, this would yield under the circumstances described and would permit the stud 5 to make its normal position between the two lugs 7 and 7 The speed regulator may be formed as a permanent unitary part of the gun or 1tma be formed as an attachment adapted to be readily secured to or removed from a previously or separately constructed gun. I prefer and have shown the speed regulator constructed in the form of an attachment. When so constructed there is provided a main frame or bracket upon which the other parts of the regulator are mounted. As il lustrated this bracket comprises two main parts 29 and 30 which are adapted to embrace the lower part of the gun being connected together by means of bolts 31. The cylinder 9 and the metal forming the passageway 19 are integral parts of the bracket member 29 and thus the said member has an. integra extension 29 to which the lever 7 is pivoted.

When the regulator is in the form of an attachment as shown I am able to conveniently provide a second adjustment whereby the effectiveness of the retarding action may be regulated. I have already described the adjustment of the retarding action by means of the valve 21. This adjustment may be supplemented by adjusting the parts so as to change the angle of movement of the lever 7 or to change the position of the point at which the reciprocating member is released for free independent movement. This last mentioned adjustment is effected by loosening the bolts 31 to release the main attachment bracket and by moving the entire attachment longitudinally of the gun. Fig. 1 shows the attachment in one position providing a relatively small angle of oscillation of the lever and Fig. 8 shows the attachment in another position providing a much greater angle of oscillation of the lever. The dotted line position in Fig 3 shows the reciprocating member 5 in the position whereit first engages the lug 5 during recoil movement and the full line position in Fig. 3 shows the said member and the parts of the regulator in the fully recoiled position. From an inspection of Figs. 1 and 3 it will be seen that with the parts in the position shown in Fig. 3 the reciprocating member 5 is subjected to the retarding action during a longer portion of its stroke, the result being that the retarding action is considerably increased.

Ordinarily sufficient retarding effect can be obtained with the attachment in a position such as shown in Fig. 1. lVhen the attachment is in this position it can be rendered entirely inoperative, without bodily movement thereof, by manually turning the lever 7 in the counter-clockwise direction to its rearmost position. The member 5 is then free to reciprocate without engaging the lever 7.

lVhat I claim is:

1. The combination with an automatic firearm comprising a recoil-actuated reciprocah ing member, of a regulating element automatically engaging the said reciprocating member during the initial part of its counterrecoil movement and automatically disengaged therefrom immediately thereafter to permit the reciprocating member to complete its counter-recoil movement independently of the regulating element, means connected with the said regulating element for thereby retarding the said initial part of the counterrecoil movement of the reciprocating mem ber, and automatic means dependent upon the recoil movement of the firearm and acting during such movement for returning the regulating element to its position of initial engagement with the said member.

2. A combination as set forth in claim 1, wherein the means for returning the regulating elementis operated directly by the reciprocating member independently of other parts of the firearm.

3. The combination with an automatic firearm comprising a recoil-actuated reciprocating member, of aregulating lever pivoted for movement about an axis perpendicular to the direction of reciprocation, the said lever automatically engaging the said reciprocating member during the initial part of its counterrecoil movement and swinging about its pivotal axis out of engagement therewith to permit the reciprocating member to complete its counter-recoil movement independently of the regulating lever, means connected with the said regulating lever for thereby retardpressed latch on "the lever automatically en-.

gaged by the said reciprocating member near the end of its recoil movement, the said latch remaining in engagement with the said mem her during the initial part of its counterrecoil movement and swinging with the lever about the pivotal xis thereof out of engagement with the reciprocatingmember to permit the latter to complete its counter-recoil movement independently of the latch and lever, means connected with the said regulat ing lever for thereby retarding the said initial part of the counter-recoil movement of the reciprocating member, and automatic means for returning the said regulating lever and latch to the position of initial engagement with the said member.

5. The combination with a recoil-actuated reciprocating member forming a part of an automatic firearm and including a transversely extending stud, of a regulating lever pivoted for movement about an axis perpendicular to the direction of reciprocation and having two lugs adapted to receive between them the said stud of the reciprocating member, the forward lug of the said lever automatically engaging the said stud during the initial part of the counter-recoil movement and swinging about the pivotal axis out of engagement therewith to permit the reciprocating member to complete its counter-recoil movement independently of the regulating lever and the rear lug of the said lever being engaged by the stud during the recoil movement thereof for returning the said regulating lever to its poistion of initial engagement with the said stud and means connccted with the said regulating lever for thereby retarding the said initial part of the counter-recoil movement of the reciprocating member.

.6. The combination with a recoil-acuated reciprocating member forming a part of an automatic firearm and including a transversely extending stud of a regulating lever pivoted for movement about an axis perpendicular to the direction of reciprocation and having two lugs adapted to receive between them the said stud of the reciprocating member, the forward lug of the said lever; comprising a spring pressed plunger automatically engaging the said studduring the initial part of its counter-recoil movement and swinging about the pivotal axis out of engagement therewith to permit the reciprocating member to complete its counterrecoil movement independently of the regulating lever and the rear lug of the said lever being engaged by the stud during the recoil movement thereof for returning the said regulating lever to its position of initial engagement with the said stud, and means connected with the said regulating lever for thereby retarding the said initial part of the counter-recoil movement of the reciprocating member.

7. The combination with an automatic firearm comprising arrecoil-actuated reciprocating member, of a regulating element engaging the said reciprocating member during the initial part of its counter-recoil.

movement and automatically disengaged therefrom immediately thereafter to permit the reciprocating member to complete its counter-recoil movement independently of the regulating element, means connected with the said regulating element for thereby retarding the said initial part of the counterrecoil movement of the reciprocating member, automatic means acting after disengagement of the said member for returning the regulating element to its position of initial engagement with the said member, and means for changing the position at which the regulating element disengages the said reciprocating member.

8. The combination with an automatic firearm comprisin a recoil-actuated reciprocating member, or a regulating element engaging the said reciprocating member during the initial part of its counter-recoil move ment and automatically disengaged therefrom immediately thereafter to permit the reciprocating member to complete its counter-recoil movement independently of the regulating element, means connected with the said regulating element for thereby retarding the said initial part of the counter-recoil movement of the reciprocating member, automatic means acting after disengagement of the said member for returning the regulating element to its position of initial engagement with the said member, and means for changing the action of the regulating element to vary the length of the said initial part of the stroke during which the said element engages the said reciprocating memher.

9. A combination as set forth in claim 8, wherein the means for returning the regulating element is operated directly by the reciprocating member independently of any other parts of the firearm.

10. The combination with an automatic firearm comprising a recoil-actuated reciprocating member, of a regulating lever pivoted for movement about an axis perpendicular to the direction of reciprocation, the said lever antomatically engaging the said reciprocating member during the initial part of its counter-recoil movement and swinging about its pivotal axis out of engagement therewith to permit the reciprocating member to con:- plete its counter-recoil movement independently 01" the regulating lever, means connected with the said regulating lever for thereby retarding the said initial part of the counterrecoil movement of the reciprocating member, automatic means acting after disengagement of the said member for returning the said regulating lever to its position of inital engagement with the said member, and means for changing the angle of movement of the lever and for thus varying the length of the said initial partof the stroke during which the said lever engages the said reciprocating member.

11. The combination with an automatic firearm comprising a recoil-actuated reciprocating member, of a regulating lever pivoted for movement about an axis perpendicular to the direction of reciprocation, the said lever automatically engaging the said reciprocating member during the initial part of its counter-recoil movement and swinging about its pivotal axis out of engagement therewith to permit the reciprocating member to complete its counter-recoil movement independently of the regulating lever, means connected with the said regulating lever for thereby retarding the said initial part of the counter-r coil movement of the reciprocating member, automatic means acting after disengagement of the said member for returning the sale regulating lever to its position of initial engagement with the said member, and means for changing the position of the said pivotal axis and Ior varying the length of the said initial part of the stroke during which the said lever engages the said reciprocating member.

12. The combination with an automatic firearm comprising a recoil-actuated reciprocating member, of a regulating element automatically engaging the said reciprocating member during the initial part of its counterrecoil movement and automatically disengaged therefrom immediately thereafter to permit the reciprocating member to complete its counter-recoil movement independently of the regulating element. means connected with the said regulating element for thereby retarding the said initial part of the counterrecoil movement of the reciprocating member, the said means permitting free move ment of the regulating element in the recoil direction, and automatic means acting after disengagement of the said member for returning the regulating element to its position of initial engagement with the said member.

13. The combination with an automatic firearm comprising a recoil-actuated reciprocatin member, of a regulating element automatically engaging the said reciprocating member during the initial part of its counterrecoil movement and automatically disengaged therefrom immediately thereafter to permit the reciprocating member to complete its counter-recoil movement independently o1 the regulating element, means connected with the said regulating element for thereby retarding the said initial part of the counterrccoil. movement of the reciprocating member, means for changing the retarding action of the last said means, and automatic means acting after disengagement of the said *memher for returning the regulating element to its position of initial engagement with the said member.

A. The combination with an automatic firearm comprising a recoil-actuated reciprocating member, of a regulating element auto matically engaging the aid reciprocating member during the initial part of its counterrecoil movement and automatically disengaged therefrom immediately thereafter to permit the reciprocating member to complete its counter-recoil movement independently of the regulating element, automatic means acting after disengagement of the said member for returning the said regulating element to its position of initial engagement with the said member, and retarding means comprising a cylinder and a piston movable therein one of which is directly connected with the said regulating element, the said ieans including a passage and a check valve therefor permitting fluid to flow freely from one end of the cylinder to the other during recoil but preventing flow therethrough in the reverse direction during counter-recoil.

15. The combination with an automatic firearm comprising a recoil-actuated reciprocating member, of a regulating element automatically engaging the said reciprocating member during the initial part of its counter: recoil movement and automatically disen' gaged therefrom immediately thereafter to permit the reciprocating member to complete its counter-recoil movement independently of the regulating element, automatic means acting after disengagement of the said member for returning the said regulating element to its position or initial engagement with the said member, and retarding m ans comprising a cylinder and a piston relatively movable therein one of which is directly connected with the said regulating element, the said means including a passage and a check valve therefor permitting fluid to flow freely from one end of the" cylinder to the other during recoil but preventing flow therethrough in the reverse direction during counter-recoil and the said means also including a second passage of adjustable cross-section for permitting a limited flow from one end of the cylinder to the other in the last said direction.

16. A regulating attachment for an automatic firearm having a recoil-operated reciprocating member, the said attachment Comprising in combination a bracket adapted to be detachably secured to a firearm, a regulating element on the bracket adapted to engage the said reciprocating member during the initial part of its counter-recoil movement and to be automatically disengaged therefrom immediately thereafter to permit the reciprocating member to complete its counter-recoil movement independently of the regulating element, means on the bracket connected with the said regulating element for thereby retarding the said initial part of the counter-recoil movement of the reciprocating member and automatic means acting after disengagement of the said member for returning the regulating element to its position of initial engagement with the said member.

17. A combination as set forth in claim 16,

wherein the means for returning the regulating element is operated directly by the reciprocating member independently of any other parts of the firearm.

18. A regulating attachment for an auto matic firearm having a recoil-operated reciprocating member, the said attachment comprising in combination a bracket adapted to be detachably secured to a firearm and to be adjusted longitudinally therealong, a regulating lever pivoted to the bracket for movement about an axis perpendicular to the direction of reciprocation, the said lever automatically engaging the said reciprocating member during the initial part of its counter-recoil movement and swinging about its pivotal axis out of engagement therewith to permit the reciprocating member to complete its counter-recoil movement independently of the regulating lever and the posltion of dis engagement being determined by the adjust ment of the bracket on the gun, means on the bracket connected with the said regulating lever for thereby retarding the said initial part of the counter-recoil movement of the reciprocating member, and automatic means acting during the recoil movement of the said member for returning the said regulating lever to its position of initial engagement with the said member.

In testimony whereof I have hereunto set my hand this 9th day of July, 1927.

CHRISTIAN PFEIFFER. 

